Part 12

Learn how to defeat Sectoids, Mechtoids, Seekers, and Thin Men in XCOM: Enemy Within. Includes stats and strategies.

Sectoids: Sectoids can perform mind merges with each other, creating a blue aura link. The receiving unit gains 1 extra HP and 25 extra Will, increasing their chance to critical hit. Killing the casting unit results in both the casting and receiving units dying. Only kill the casting unit when it is convenient and not worth risking soldiers in hazardous positions.

Mechtoids: Mechtoid squads consist of usually 2 Sectoids and a large bipedal mech with gun arms. The Mechtoid immediately goes on overwatch when sighted, while Sectoids generally run around. This unit is difficult early game, dealing 9 damage on Classic (11 on Impossible, 7 on Normal, 6 on Easy) and can shoot twice per turn. It is one of the first units with a defense bonus. By the time you encounter them, you should have lasers, MECs, or advanced soldier classes available. Two hits from a tier 2 Mech weapon should kill a Mechtoid. If you fail to kill the Mechtoid on its first turn, accompanying Sectoids will mind merge with it, granting +6 HP and a shield that halves incoming damage. Killing the mind-merged unit only damages the Mechtoid by 3 points (it has 22 HP on Classic). Use full (cover (press the cover button to crouch behind walls or objects)) as much as possible and focus fire on the Mechtoid. Consider using heavies with 'heat ammo' or fielding more MECs with tier two weapons if they prove troublesome.

Seekers: Seekers are flying octopuses that cloak when spotted and then move to strangle soldiers. There is typically a one-turn delay between strangling attempts. A unit that gets strangled loses 2 HP per turn, plus additional HP for the number of turns spent strangled. When freed, a unit suffers a 75% move penalty and a 50% Aim penalty (but not rocket aim) for being 'short of breath'. Seekers are not very deadly unless you have heavily wounded soldiers or everyone is immune to strangling. If everyone is immune, Seekers will shoot plasma bolts (3 damage), which can be dangerous due to their cloaking ability and guaranteed point-blank shots. You can bump into cloaked Seekers, which will not decloak them, but area of effect (AoE) lockons still occur. Hitting a cloaked Seeker with a grenade causes them to decloak and damages them. Getting strangled deals 2 damage instantly; if a wounded soldier has only 2 HP, they can be instantly killed. Seekers are not a major threat and can be an excuse to get carapace armor early.

Thin Men: Thin Men have high stats for their early availability. On Classic, they have a base accuracy of 75 and a light plasma rifle that grants +10 Aim. They are among the few enemies using light plasma rifles exclusively, capable of killing a unit in full (cover) (45% chance to hit). They tend to run away and jump to roofs when encountered, often activating additional squads in cramped maps. Only laser weapons can kill a Thin Man in one shot. With only 4 soldiers with average accuracy, range penalties, high ledges, and (cover) penalties, your chance to hit can be as low as 0-20%. MECs have low defense, and Thin Men have high damage and critical hit chances, making them a threat to MECs. Thin Men gain a +20 Aim bonus from elevation, reaching 105 Aim. If they cannot hit, they can use an insta-hit poison that reduces Aim and deals 3 HP over several turns. The best strategy is to have snipers with opportunist on overwatch to shoot Thin Men running for (cover). Snipers with squad sight can also provide fire support for killing entrenched Thin Men.